For some items, it is necessary to appropriately manage the environmental conditions such as temperature, humidity, vibration, gas, and barometric pressure when the items are transported from their manufacturing premises to their consuming regions. For example, there are some food items that become unsuitable for consumption because they go rotten or lose taste when they are put under an environment condition such as a high temperature or a low temperature. In addition, there are some food items the qualities of which deteriorate when they are put under the environmental condition of high humidity, the environmental condition of the concentration of oxygen present in the air, or the like. Furthermore, there are some items that are damaged when unforeseen vibrations are applied to the some items.
In order to cope with the abovementioned problems, when items that are targets are transported or stored, measures are taken in which the items are housed in airtight containers, or temperature management and humidity management using air conditioning devices, vibration management, and the like are executed in transport containers, transport cargo trucks, or property rooms.
However, there are some cases where, owing to the failures of the devices or mistakes in the above management, the above management items depart from their respective management ranges. Therefore, in order to judge whether such departures have occurred or not, the following devices and methods are proposed.
Patent Literature 1 discloses a method in which a temperature-indicating member that changes its color in accordance with temperature is attached to an item that is a management target, and a code shown by a barcode adjacent to the item and the color of the temperature-indicating member are read by a reading device. In addition, a method, in which the temperature history is estimated by analyzing the read codes and the read color data, is disclosed. Furthermore, a method, using which a temperature-indicating member the color of which varies in accordance with temperature is produced, is also disclosed.
Patent Literature 2 discloses a method in which plural barcodes whose colored or non-colored bars change in accordance with a temperature range at the time of barcode reading are attached to items, and only a single barcode is read on the basis of a temperature at the time of barcode reading. Furthermore, a method, in which these read data are transmitted to a computer, and the quality management of the items is executed, is disclosed.
Patent Literature 3 discloses a method using which a detection agent sheet, the color of which changes in accordance with oxygen atmosphere, is produced. The above method is a method using which the detection agent sheet, the color of which is red when the sheet is kept airtight after being manufactured, but becomes blue when the sheet is freed from the airtight state, is produced.